Crankpin turning tool



Patented Oct. 22, 1940 UNITED STATES PATENT OFFICE 11 Claims.

This invention relates to turning tools, particularly for truing thepins of a crankshaft Without removal thereof from its operatingposition, and has for its principal object to provide a tool of thischaracter which is extremely accurate'in operation and smoothly facesthe cylindrical surfaces of a crankpin as well as the fillets and cheeksof the crank.

Other objects of the invention are to provide a tool of this characteradapted for turning crankpins of different diameter with extremeaccuracy; to provide the tool with a secure cutter mounting to avoidchatter during cutting operation of the tool; to provide a cutter havinga cutting edge arranged to engage the crankpin in a plane passingthrough the axis thereof regardless of its diameter, the diameter, ofcourse, being within the capacity of the tool; to provide the tool withinterchangeable cutters and tool positioning guide pins corresponding tothe width of the crankpin to be acted upon; and to provide a cutterhaving a plurality of cutting edges any one of which may be used byselectively positioning the cutter.

Further objects of the invention are to provide a tool that is readilyapplied to the crankpin; to provide a tool with means to compensate forwear of the guide pins securing the respective sections thereof; and toprovide adjusting screws with a micrometer scale to indicate the amountof cut upon each revolution of the tool.

In accomplishing these and other objects of the invention, ashereinafter pointed out, I have provided improved details of structure,the preferred form of which is illustrated in the accompanying drawing,wherein:

Fig. 1 is a perspective view of the lower portion of a crankcase of aninternal combustion engine, showing the oil pan removed and my improvedturning tool applied to one of the crankpins.

Fig. 2 is a sectional view through the tool.

Fig. 3 is a side elevational view of the upper half of the tool, part ofwhich is broken away to show the adjusting screw for tightening theguide pins in case of wear.

Fig. 4 is a section on the line 4 4 of Fig. 2.

Fig. 5 is a detail perspective view of the parts of the turning toolshown'in disassembled spaced relation to better illustrate theconstruction 0 thereof.

Referring more in detail to the drawing:

I designates a turning tool constructed in accordance `with the presentinvention, and which includes a substantially ring-like body 2 composedof mating, arcuate sections 3 and 4. The

` commodate the guide pins 9 andIII which are sections 3 and 4 are ofless width than the minimum width of pin on which the tool is to be usedso that it is freely rotatable about the axis of a pin a between thecheeks b and c of a crank d, The inner arcuate faces 5 and 6 of therespective sections are of suitable diameter to accommodate the largestsize pin for which the tool is to be used, and the outer arcuate faces 1and 8 are of suihcient diameter to give the required rigidity and metalnecessary in mounting the connecting 1 guide pins 9 and I0 by which thesections are interconnected. The adjacent end faces II and I2 of therespective sections extend on parallel planes so that the sections maybe brought closely together when applied to a crankpin of miniu mumdiameter.

Extending inwardly from the faces I2 of the respective sections arecylindrical bores I3 to acseated therein and drawn tightly against thebottom I4 of the bores by fastening devices, such as llister screws I5,having heads countersunk within bores I6 formed within the arcuate faces1 and 8 of the respective sections and in axial registry with the boresI3. The Shanks n of the 25 screws extend through axial openings I3 inthe sections and into threaded sockets I9 formed in the ends of therespective guide pins. The heads of the screws are provided with hexagonshaped sockets 2li or the equivalent, whereby the screws 8 are adaptedto be rotated with the aid of a suitable tool to tighten the pins rmlywithin their respective bores I3. The guide pins are of sufilcientlength to project from the faces I2 to form guide portions slidablyreceivable in registering 85 bores 2I extending inwardly from the facesII at the opposite sides of the respective sections. The projection ofthe pin I0 is greater than that of the pin 9 so that the pin I0 iscaused to enter its receiving bore ahead of the pin 9 to facilitateassembly, as later described.

The pins 9 and I0 are provided with axial bores 22 having internalthreads to be engaged by the threaded shanks 23 of adjusting screws 24,the shanks of the adjusting screws being extended through openingsextending through the bottom of the bores 2l toward the outer peripheryof the sections where they terminate in counterbores 25 to accommodatethe cylindrical heads 26 of the adjusting screws. within one side of thecounterbore and are provided with micrometer scales 21, the divisions ofwhich are adapted to register with zero scales 23 on thev respectivesections, as best shown in Fig. 5. The heads of the adjusting screws areprovided The heads 26 are exposed 50 with hexagonal sockets 29 for theinsertion of a suitable tool whereby the screws are rotated to threadthe shanks thereof to and from the threaded bores 22 of the guide pins,thereby connecting and disconnecting the sections and effectingadjustment in spacing thereof to accommodate crankpins of differentdiameters.

In order to automatically move the sections apart upon unthreading ofthe adjusting screws, the bores 2| have coil springs 30 sleeved over theshanks of the adjusting screws and having one end bearing against thebottom of the bores 2| and their opposite ends against the ends of theguide pins.

After the tool has been in use for some time, it is possible that theguide pins may wear relatively to the bores 2|, which wear wouldinterfere with successful operation of the tool. The ends of thesections having the I`bores 2| are therefore slotted as shown at 3|,with the slots intersecting openings 32 that are formed radially in theouter arcuate faces l and 8 of the sections and intersect with the bores2| to provide sufflcient flexibility on the respective sides ofthe guidepins to permit snug clamping thereof within their respective bores byiillister screws 33 having their heads 34 rotatably mounted in acounterbored opening at one side of the sections and their shanks 35threaded in openings 36 at the opposite sides of the sections. Formed inthe arcuate faces 1 and 8 of the sections are sockets 31 whereby asuitable handle or bar 38 may be inserted to effect rotation of thetool, as later described.

In the form of the invention illustrated, the section 3 constitutes asupport for a cutter 39 and a plunger assembly 49, while the section 4supports spaced seating plates 4| and 42 for seating the tool againstthe crankpin a. 'I'he cutter 39 is best shown in Fig. 5 and constitutesa flat blade having side faces 43, edge faces 44, and end faces 45. Thejunctures of the faces 43 and 44 form cutting edges 46 adapted to removematerial from the circumference of the pin a and the juncture of thefaces 43 with the end faces 45 form cutting edges 41 to remove materialfrom the cheeks b and c of the crank. The corners of the cutter arerounded, as atv 48, to form the llets e of the crank so that thecrankpin, cheek faces and fillets are simultaneously surfaced uponactuation of the tool, as later described.

'I'he cutter 38 is seated in a transverse groove 49 extending inwardlyof the arcuate face 5 and which forms a shoulder 50 against which thecutter is rigidly secured by a wedge member 5| having one side bearingagainst the cutter and its opposite side against the opposite side orshoulder 52 of the groove as shown in Fig. 2. The wedge plate is drawninto wedging relation with the cutter by flllister screws 53 havingtheir heads 54 rotatably mounted in oounterbores of the wedge and theirshanks 55 extending through registering openings 56 into threadedsockets at the bottom of the groove. The shoulder 50 is so positioned inthe section 4 that when one side face of the cutter is wedgedthereagainst the opposite side face will lie in a plane extendingthrough the axis of a crankpin to which the tool is applied. The cuttingedge 46 thereof therefore contacts the cylindrical surface of the pin atthe diametrical axis thereof and the adjacent edge face 44 cooperateswith the cylindrical surface to provide sufcient clearance at theretractive side of the cutter when the tool is rotated about the axis ofthe crankpin in the direction of the arrow.

In order that the cutting edge of the cutter, when positioned as shownin Fig. 2, will at all times remain in a diametrical plane with respectto the crankpin regardless of the diameter thereof, I have found thatthe cutter must be positioned at substantially 24 from the median lineof the arcuate face 5 of the section 3. It is also essential that theplates 4| and 42 have plane surfaces for tangentially contacting thecylindrical surface of the crankpin, that the seating plate 42 belocated directly opposite the cutter and that the plane surfaces belocated at right angles to each other, as shown in Fig. 2. The seatingplates 4| and 42 preferably have dovetail edges 51 and 58 to engage indovetail grooves 59 provided inthe arcuate face 6 of the section 4. Thepin contacting faces 69 of the seating plates are preferably flat sothat they extend tangentially with respect to the cylindrical surface ofthe'crankpin. In order to firmly retain the seating plates 4| and 42 intangential contact with the crankpin to be resurfaced, the'section 3 isprovided with the plunger assembly 40 which is located thereindiametrically opposite to the midpoint between the seating plates 4| and42. The plunger assembly includes a bar 6| slidable in a slot 62extending transversely of the arcuate face 5. The bar 6| has a central,internally threaded shank 63 slidable in a bore 64 registering with theslot 62. The bore 64 has an internal shoulder 65 to be engaged by acollar 66 on the shank 63. The inner end of the bore terminates short ofthe outer face of the section 3 to form a spring seat 61. Formed in thearcuate face 1, in axial alignment with the bore 64, is a bore 68 toaccommodate the head 69 of a retaining screw 10, the shank of whichextends through a guide opening and into the threaded socket of theshank 63 In order to pressingly retain the plunger against the work, theshank of the screw carries a coil spring '|2 having one end bearingagainst the spring seat and its opposite end against the shank 63 asclearly shown in Fig. 2.

In order to cooperate with the cutter in centering the tool between thecheeks b and c of the crank d, the section 4 is provided with atransverse opening 13 in which is slidably mounted a guide pin `|4corresponding in length to the cutkter so that the ends 15 of the pinengage the respective cheeks, thereby retaining the outer side faces ofthe tool parallel with the cheeks b and c.

In using a tool constructed as described for resurfacing a crankpin a,it is only necessary to remove the oil pan of the engine. The connectingrod bearing is then removed from the crankpin to permit application ofthe turning tool, it being unnecessary to remove the connecting rod orpiston. When the piston is moved to the top of the cylinder theconnecting rod is carried therewith which leaves sufficient roomtherebelow to operate the tool. The adjusting screws 24 of the turningtool are then removed from the guide pins so that the sections of thetool may be separated to permit application thereof to the crankpin.Prior to application of the tool, however, a cutter 39 of proper lengthis inserted in position within the section 3 and securely tighttened bythe wedge element. then placed about the pin to be surfaced so that theguide pin ||I enters the bore 2| of the section 4 prior to entrance ofthe guide pin 9 in the bore 2| of the section 3. This is an importantfeature since it facilitates mounting of the tool on the crankpin. Theadjusting screws are then The sections are reapplied to secure thesections together and draw the sections 3 and 4 so that the seatingplates 4I and 42 contact one side of the bearing pin and the plunger 6Ithe opposite side, thereby centering the tool for rotation about theaxis of the pin. The adjusting screws are drawn up until the cuttingedge of the cutter engages the cylindrical periphery of the pin so thatwhen a bar is inserted in the sockets 31 to rotate the tool in thedirection of the arrow, Fig. 2, surface is removed from the crankpin toform a true cylinder. Since the cutting edge of the cutter is at alltimes kept in substantially the diametrical axis of the pin, and theplates 4I and 42 seated against the opposite sides thereof by theplunger, the tool will not chatter when rotated. The cut is, therefore,smoothly uniform and true cylindrically with respect to the axis of thepin. The ends of the cutter and the rounded corners thereof also formcutting edges which true up the cheeks b and c as well as the fillets atthe ends of the pin. The amount of each cut may be noted by themicrometer scales on the heads of the adjusting screws so that thedesired reduction may be e'iected in the size of the pin.

.When the tool is to be applied to a smaller shaft, as` shown by thedotted lines in Fig. 2, the plates 4I and 42 will maintain theirtangential contact with the smaller shaft and the drawing together ofthe sections will move the cutting edge of the cutter downwardly towardthe smaller shaft in a plane parallel with the vertical axis asrespectively indicated by the plane lines J6 and l1.

From the foregoing it is obvious that I have provided a turning tooladapted for accurate work and which will simultaneously finish all ofthe bearing surfaces of a crankpin with a single application of thetool. It is also obvious that the tool is readily applied to a crankpinwithout removing the crankshaft from its operating position since thetool may be readily rotated about the shaft by alternating engagement ofthe turning bar with respect to the sockets 31 in the respectivesections.

What I claim and desire to secure by Letters Patent is:

l. A device of the character described including a pair of matingsections having arcuate inner faces, adjusting means connecting thesections about a cylindrical object to be surfaced, a pair of seats inthe arcuate face of one of the sections arranged to engage thecylindrical surface of said object, a cutter carried by the othersection and located diametrically opposite one of the seats, a plungerslidable in the section having the cutter, a bar carried by the plungerand provided with an edge portion for contact with said cylindricalsurface, a spring engaging the plunger and urging the bar toward saidseats to retain said seats in contact with the cylindrical surface actedupon by the cutter, and a screw having threaded connection with theplunger.

2. In a device of the character described, a pair of mating sectionshaving arcuate inner faces, adjusting means connecting the arcuatesections about a cylindrical object to be surfaced, a pair of seats inthe arcuate face of one of the sections having plane surfaces arrangedto engage tangentially the cylindrical surface of said object with saidpoints of tangency substantially 90 part, a cutter carried by the othersection and having a cutting edge located in a plane offset at an angleof substantially 24 from a plane pas-sing through the axes of saidarcuate inner faces, and a spring pressed plunger slidable in thesection having the cutter and offset on the opposite side of said axialplane to retain said seats in contact with the cylindrical surface actedupon by the cutter. i

3. In a device for surfacing crankpins of crankshafts, a pair of matingsections having substantially arcuate inner faces, meansadjustablyconnecting the sectionsabout a crankpin to be surfaced, a pair of seatsin the face of one` of the sections arranged to engage the cylindricalsurface of the pin, a cutter carried by the other section and locateddiametrically opposite one of the seats, and a lateral guide pinslidably mounted in the section having the seats with its axis extendingparallel with the axes of the sections to cooperate with the cutter inmaintaining the sections in right-angular relation to the axis of thecrankpin.

4. A device for surfacing crankpins of crankshafts including a pair ofmating sections having substantially arcuate inner faces, adjustingmeans connecting the sections about a crankpin to be surfaced, a pair ofseats in the arcuate face of one of the sections arranged to engage thecylindrical surface of the crankpin, a cutter carried by the othersection, said section having the cutter being provided with a radialbore extending therethrough and provided with a spring engaging seat, a.plunger slidable in the bore, a spring having one end engaged againstthe plunger and the other against said seat, and a screw slidable in thebore and having threaded connection with the plunger to adjust spacingof the plunger relatively to said seats.

5. In a turning tool of the characterl described, a pair of matingarcuate sections, parallel guide pins inl opposite ends of therespective sections and slidably engageable in aligning bores in theopposite facing ends of the sections, adjusting screws rotatably mountedin the ends of the sections having the bores and threadedly engaging theguide pins to move said sections toward each other, a spring on eachadjusting screw to move the sections apart when the rotation of thevscrews is reversed, a cutter supported by one of the sections, andseating plates supported in the other section and cooperating with thecutter tov engage a cylindrical surface of a crankpin upon manipulationof the adjusting screws.

6. In a turning tool of the character described, a pair of matingarcuate sections, guide pins in opposite ends of the respective sectionsand slidably engageable in aligning bores in the facing ends of thesections, adjusting screws rotatably mounted in the sections andthreadedly engaging the guide pins to move 'said sections toward eachother, a cutter supported by one of the sections, seating platessupported on the other section and cooperating with the cutter to engagea cylindrical surface of a crankpin upon manipulation of the adjustingscrews, and springs separating said sections upon unthreading of theadjusting screws to move the cutter and seating plates away from saidcrankpin, said adjusting screws having graduations on heads thereofregistrable with markings on the sections for spacing the sections toposition the cutter with respect to said seating plates.

7. In a turning tool of the character described, a pair of matingarcuate sections, guide pins in opposite ends of the respective sectionsand slidably engageable in aligning bores in the facing ends of thesections, adjusting screws rotatably mounted in the sections andthreadedly engaging the guide pins to mo've said sections toward eachother, a cutter supported by one of the sections, seating platessupported in the other section and cooperating with the cutter to engagea cylindrical surface of a crankpin upon manipulation of the adjustingscrews, a spring sleeved over each adjusting screw and having separatingcontact between a respective section and the guide pin carried by theother section whereby said sections are spread apart upon unthreading ofthe adjusting screws to move the cutter and seating plates away fromsaid crankpin, and clamping screws for tightening the guide pins in saidbores.

8. In a turning tool of the character described, a pair of matingarcuate sections, guide pins in opposite ends of the respective sectionsand slidably engageable in aligning bores in the op posite facing endsof the sections, adjusting screws rotatably mounted in the sections andthreadedly engaging the guide pins to move said sections toward eachother, springs urging said sections apart, a cutter supported by one ofthe sections, seating plates supported in the other section andcooperating with the cutter to engage a cylindrical surface of acrankpin upon manipulation of the Kadjusting screws, and clamping screwsfor clamping said guide pins in said bores.

9. In a device of the character described, a pair of sections havingarcuate inner faces one of which is provided with a wedge shaped groovehaving one side face thereof substantially paral- 1e1 with a planeoffset substantially 24 with respect toa plane passing through the axesof said arcuate faces, a cutter inserted in said groove and engaging oneside thereof, a wedge block inserted in the groove between the cutterand the op'posite side thereof, screws for retaining the wedge block toanchor said cutter,

asias-ss and seating plates supported in the arcuate face of the othersection and having plane faces respectively located substantially 90apart and with one of said plates located at right angles to said osetplane.

10. In a turning tool, a pair of sections having arcuate inner faces,spaced adjustable guide screws connecting said sections with their axesparallel with a plane intersecting the axes of said arcuate faces, acutter radially supported by one of the sections in a plane oifsetsubstantially 24 with respect to a said plane, and4 seating platessupported in the arcuate face of the other section and having planesurfaces arranged at right angles to each other, said seating platesbeing located so that one of said plane surfaces is located at rightangles to said oset plane.

11. A device of the character described including a pair of matingsections, means adjustably connecting the sections about a cylindricalobject to be surfaced, a pair of seats on one of the sections to engagesaid object, a plunger in the other section cooperatingwith said seatsto position the sections relatively tosaid object, said section havingthe plunger being provided with a cutter seat having a side. `faceparallel with one of said seats and a bot-

